Study on Spectro-Electrochemical Behaviour of Thin-Layer Polymer of 3-(9H-Carbazol-9-yl)propanenitrile

A film of electrically active poly(3-(9H-carbazol-9-yl)propanenitrile) was prepared on platinum (Pt) electrode surface by oxidative electro-polymerization of 3-(9H-carbazol-9-yl)propanenitrile monomer. The polymerization reaction was performed in a reaction medium containing monomer, and 0.1 M tetrabutylammonium tetrafluoroborate (TBABF4 ) mixture in acetonitrile (ACN) using repeated cycling at a scanning rate of 250 mV. Electrochemical polymerization of carbazole (Cz) and 3-(9H-carbazol-9-yl)propanenitrile (25 mM) were studied with cyclic voltammetry on both Pt and ITO electrodes. The structure of the poly(3-(9H-carbazol-9-yl)propanenitrile) was elucidated by nuclear magnetic resonance (1H and 13C NMR) and Fourier transform infrared (FTIR) spectroscopy. The weight average molecular weight (Mw) of the electrochemically synthesized poly(3-(9H-carbazol-9-yl)propanenitrile) was determined using gel permeation chromatography (GPC), where it was found that the Mw of the polymer is equal to 37900 g/mol. The polymer was characterized using dry conductivity measurement, scanning electron microscopy (SEM) and UV-Vis spectroscopy, while the spectro-electrochemical studies indicated that poly(3-(9H-carbazol-9-yl)propanenitrile) films revealed a green color in the oxidized state and a high transmittance in the neutral state. Moreover the poly(3-(9H-carbazol-9-yl)propanenitrile) film is soluble in common organic solvents, like DMSO, THF, NMP and DMAC. The conductivity of poly(3-(9H-carbazol-9-yl)propanenitrile) was found to be 1.62x10-4 S/cm.